Control compass



2 Sheets-Sheet l lllll G. E. BREEZE ET AL CONTROL COMPASS July 7, 1953Filed Nov. 2o, 1944 wua/wo/v GEORGE E. BREEZE RUSSELL l. MASON FIG July7, 1953 G. E. BREEZE ETAL CONTROL COMPASS 2 Sheets-Sheet 2 Filed Nov.20, 1944 FIG wvQ/YIO'US GEORGE E. BREEZE L l. MASON RUSSEL Patented July7, 1953 CONTROL COMPASS- George E. Breeze and Russell I. Mason,Waterford, Conn., assignors to the United States of America asrepresented by the Secretary of the Navy f Application November20,1944,'Serial N o. 564,256

2 Claims. (Cl. 233-223) The present invention relates to an improveddesign of control compass generally of the type described in applicationNo. 561,414, led November 1, 1944, Control Compasses, now abandoned, foruse in the directional radio sonic buoy of application No. 526,758, ledMarch 16, 1944, Remote Control or Measurement Indicating Means. TheCompasses described in No. 561,414, when tilted, gave erroneousindications because the compass element supported by two bearings tendedto become a dip-needle and would swing away from the correct north-southdirection. Compensation for this effect may be made, for a givengeographical latitude, by adjusting the weight of the counterbalance onthe rotor but this is unsatisfactory. In the present design thecondenser plate is not carried on the compass element but on a separatesmall compass carried above it and responsive to its magnetic fieldrather than that of the earth. The latter can be called thecompass-condenser element. The compass element is carried above itscenter of gravity on a single pivot and tends to remain level despiteany tilting of the case, thus avoiding the dipneedle effect, while theaction of this effect on the small follower compass-condenser element ondouble pivots is relatively so small compared tol the pull of thecompass magnet as to be negligible.

The control compass of the present application is suitable for, thoughnot limited to, use in a radio sonic buoy. As described in applicationNo. 526,758, such a buoy. might comprise a watertight buoyant body whichcontains a modulated radio transmitter and supports a directionalhydrophone from its lower end. The body is caused to rotate about avertical axis in the water by a suitable means thus rotating thehydrophone. The frequency of the transmitted carrier is varied inrelation to its angular position relative to a given meridian by meansof a condenser, one plate of which revolves with the buoy while theother is maintained stationary by means of a magnetic compass. Theoutput of the hydrophone is used to modulate the carrier wave of thetransmitter, Thus, an audible signal is transmitted when the hydrophoneis directed toward a source of sound and on a frequency whichcorresponds to the angular position of the hydrophone. However, thestructure of the buoy forms no part of the present invention, and is notfurther described herein.

It is an object of this invention to provide a control compass that willgive accurate bearings when tilted, such as would take place under the 2rolling and jarring conditions of choppy or rough water.

Another object of this invention is to provide a control compass inwhich the directing magnet is unaffected by the magnetic dip when thecase is tilted, and the dip error of the follower magnet is reduced to aminimum.

Another object of this invention is to provide a control compass inwhich the directing mechanism has no mechanical connection to thecontrol mechanism.

Another object is the provision of a device which will be economical tomanufacture, reliable in operation and which possesses all of thequalities of ruggedness and dependability in service.

In the drawings:

Fig. 1 is a vertical axial section of the device;

Fig. 2 is a plan view of the compass-element;

Fig. 3 is a detail of the condenser rotor; and

Fig. 4 is a detail of the counterweight.

The working parts of the device are enclosed by a case l0 and a cover l2held together by a clamp I4 and sealed by a gasket I8. A plug I8 in thecover permits lling the case with compass fluid. A spindle 20 alxedvertically in the bottom of the case I0 supports the main compasselement, and a yoke 22 carried on the cover I2 supports the followercompass-condenser element on bearings 24 and 26. A splash plate 28 isheld in place between the yoke and the cover. A lug 30 on the cover l2affords a means of support for the device. 1

The compass element consists of a magnet 32 supported by a plasticcarrier 34 containing a bearing 36 which rests on the spindle 20. A stud38 on the yoke 22 serves, when the instrument is assembled, to keep thecompass element on the spindle.

The follower compass-condenser element consists of a hub 40 supported inthe yoke bearings 24 and 26 by spindles 42. It carries a condenser rotor44, a follower magnet 46 and a counterweight 48. The outline of thecondenser rotor is generallyv that of a heart-shaped cam having aconstant increase of radius with angle from a minimum radius to amaximum diametrically opposite radius, and repeats this variation oneither side of the maximum radius.

A U-shaped condenser stator 50 formed of a narrow strip of metal is sosupported by a terminal post 52 in the cover I2 that its arms are onopposite sides of the rotor 44 and are directed toward its axis ofrotation.

In operation the compass element is held in 3 one position relative tothe surface of the earth by the action of the earths magnetic eld on themagnet 32. The follower magnet 46 aligns itself with the field of thecompass magnet 32 and thereby maintains the condenser rotor 44 fixed inbearing as the buoy rotates.

As the buoy rotates, the amount of overlap of the condenser rotor 44 andstator 50 varies with the change of bearing of its hydrophone. Theamount of this overlap controls the capacity between the stator 50 andsurrounding metallic parts of the buoy through the rotor 44.

The condenser rotor 44 may be installed in any desired position withrespect to the follower magnet 46; unlike the Compasses described in thereport hereinbefore mentioned, the present device as built has the rotorso arranged that Awith all elements at rest the condenser capacity isgreatest when the stator is directly west of the pivot. As the device isinstalled in the buoy, a line from the pivot through the stator is inessentially the same direction as the axis of maximum sensitivity of thehydrophone. Thus when the hydrophone is so directed that it is mostsensitive to sounds arriving from the west, the capacity of thecondenser is greatest disregarding fluid drag on the rotor. This changeof direction of maximum capacity has been made to accommodate animprovement in the indicating means in the receiving set.

In operation, the compass magnet 32 aligns itself with the earthsmagnetic eld, carrying sup-l porting frame 34 mounted upon pivot 36 withit. The frame 34 may or may not be calibrated` If calibrated the bearingmay be directly read therefrom for adjustment purposes. The controlmagnet 46 is mounted on frame 40 with the condenser rotor 44 and theframe is pivoted in bearings 24 and 26. The field of the compass magnet32 is so strong inside the casing I 0 that the small control magnet 46aligns itself therewith at all times moving rotor 44 between plates 50of the condenser corresponding to the position of the compass magnet 32.The drag of the control magnet 46 on the compass magnet 32 does notintroduce errors in the compass magnet because the counter torque ismagnetic instead of frictional. Furthermore, compass magnet 32 can betilted in any position by rough water or the like and the control magnet46 still faithfully follows the magnetic eld without introducingadditional frictional torque. Since rotor 44 is always aligned with thecompass magnet the capacity of the condenser is proportional to theazimuth of the casing.

, compass magnet element pivotally supported by said vertical spindle,means for preventing said compass magnet'element from movement off saidvertical spindle, said means comprising a yoke supporting means integralwith said casing cover and projecting within said casing to a pointabove said spindle, said yoke supporting means having facing verticallyspaced bearings secured thereon, a follower compass element havingoppositely facing vertical supporting spindles rotatably mounted in saidfacing vertically spaced bearings, said follower compass elementcomprising a hub portion, a follower magnet and a horizontal condenserrotor xed to said hub portion, said horizontal condenser rotor beingheart-shaped and having mirror symmetry relative to a plane containingthe rotor axis and the point of maximum radius, a condenser statorcomprising two vertically spaced horizontal arms electricallycooperating with said horizontal condenser rotor, and a verticalterminal post secured to said casing cover and xedly supporting saidcondenser stator.

2. The invention as defined in claim l but further characterized by saidcasing having compass fluid therein, said casing cover having aremovable plug to permit nlling said casing with said compass iluid, anda splash plate secured to said yoke supporting means to preventexcessive movement of said compass fluid.

GEORGE E. BREEZE.` RUSSELL I. MASON.

References Cited in the file 0f this patent UNITED STATES PATENTS iCarter Nov. 28, 1944

